mathieu/granite-rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Handle all arbitrary loop nesting in break type errors

Browse source
This commit is contained in:
Esteban Küber 2023-09-25 21:57:22 +00:00
parent 58adfd84e2
commit 3747ef5d6f
3 changed files with 137 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
compiler/rustc_hir_typeck/src/demand.rs
View file

@ -583,7 +583,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// loop, so we need to account for that.
direct = !direct;
}
if let hir::ExprKind::Loop(_, label, _, span) = parent.kind
if let hir::ExprKind::Loop(block, label, _, span) = parent.kind
&& (destination.label == label || direct)
{
if let Some((reason_span, message)) =
@ -594,25 +594,39 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
span,
format!("this loop is expected to be of type `{expected}`"),
);
break 'outer;
} else {
// Locate all other `break` statements within the same `loop` that might
// have affected inference.
struct FindBreaks<'tcx> {
label: Option<rustc_ast::Label>,
uses: Vec<&'tcx hir::Expr<'tcx>>,
nest_depth: usize,
}
impl<'tcx> Visitor<'tcx> for FindBreaks<'tcx> {
fn visit_expr(&mut self, ex: &'tcx hir::Expr<'tcx>) {
let nest_depth = self.nest_depth;
if let hir::ExprKind::Loop(_, label, _, _) = ex.kind {
if label == self.label {
// Account for `'a: loop { 'a: loop {...} }`.
return;
}
self.nest_depth += 1;
}
if let hir::ExprKind::Break(destination, _) = ex.kind
&& self.label == destination.label
&& (self.label == destination.label
// Account for `loop { 'a: loop { loop { break; } } }`.
|| destination.label.is_none() && self.nest_depth == 0)
{
self.uses.push(ex);
}
hir::intravisit::walk_expr(self, ex);
self.nest_depth = nest_depth;
}
}
let mut expr_finder = FindBreaks { label, uses: vec![] };
expr_finder.visit_expr(parent);
let mut expr_finder = FindBreaks { label, uses: vec![], nest_depth: 0 };
expr_finder.visit_block(block);
let mut exit = false;
for ex in expr_finder.uses {
let hir::ExprKind::Break(_, val) = ex.kind else {
continue;
@ -631,10 +645,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
ex.span,
format!("expected because of this `break`"),
);
exit = true;
}
}
if exit {
break 'outer;
}
}
break 'outer;
}
}
}

36
tests/ui/loops/loop-break-value.rs
View file

@ -107,6 +107,7 @@ fn main() {
}
break; //~ ERROR mismatched types
};
let _ = 'a: loop {
loop {
break; // This doesn't affect the expected break type of the 'a loop
@ -119,6 +120,41 @@ fn main() {
break 'a; //~ ERROR mismatched types
};
loop {
break;
let _ = loop {
break 2;
loop {
break;
}
};
break 2; //~ ERROR mismatched types
}
'a: loop {
break;
let _ = 'a: loop {
//~^ WARNING label name `'a` shadows a label name that is already in scope
break 2;
loop {
break 'a; //~ ERROR mismatched types
}
};
break 2; //~ ERROR mismatched types
}
'a: loop {
break;
let _ = 'a: loop {
//~^ WARNING label name `'a` shadows a label name that is already in scope
break 'a 2;
loop {
break 'a; //~ ERROR mismatched types
}
};
break 2; //~ ERROR mismatched types
};
loop { // point at the return type
break 2; //~ ERROR mismatched types
}

82
tests/ui/loops/loop-break-value.stderr
View file

@ -1,3 +1,21 @@
warning: label name `'a` shadows a label name that is already in scope
--> $DIR/loop-break-value.rs:136:17
|
LL | 'a: loop {
| -- first declared here
LL | break;
LL | let _ = 'a: loop {
| ^^ label `'a` already in scope
warning: label name `'a` shadows a label name that is already in scope
--> $DIR/loop-break-value.rs:148:17
|
LL | 'a: loop {
| -- first declared here
LL | break;
LL | let _ = 'a: loop {
| ^^ label `'a` already in scope
error[E0425]: cannot find value `LOOP` in this scope
--> $DIR/loop-break-value.rs:95:15
|
@ -164,12 +182,19 @@ LL | break "asdf";
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:21:31
|
LL | let _: i32 = 'outer_loop: loop {
| - ---- this loop is expected to be of type `i32`
| |
| expected because of this assignment
LL | loop {
LL | break 'outer_loop "nope";
| ^^^^^^ expected `i32`, found `&str`
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:73:26
|
LL | break;
| ----- expected because of this `break`
LL | break 'c 123;
| ^^^ expected `()`, found integer
@ -218,7 +243,7 @@ LL | break;
| help: give it a value of the expected type: `break value`
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:119:9
--> $DIR/loop-break-value.rs:120:9
|
LL | break 'a 1;
| ---------- expected because of this `break`
@ -230,7 +255,58 @@ LL | break 'a;
| help: give it a value of the expected type: `break 'a value`
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:123:15
--> $DIR/loop-break-value.rs:131:15
|
LL | break;
| ----- expected because of this `break`
...
LL | break 2;
| ^ expected `()`, found integer
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:140:17
|
LL | break 2;
| ------- expected because of this `break`
LL | loop {
LL | break 'a;
| ^^^^^^^^
| |
| expected integer, found `()`
| help: give it a value of the expected type: `break 'a value`
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:143:15
|
LL | break;
| ----- expected because of this `break`
...
LL | break 2;
| ^ expected `()`, found integer
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:152:17
|
LL | break 'a 2;
| ---------- expected because of this `break`
LL | loop {
LL | break 'a;
| ^^^^^^^^
| |
| expected integer, found `()`
| help: give it a value of the expected type: `break 'a value`
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:155:15
|
LL | break;
| ----- expected because of this `break`
...
LL | break 2;
| ^ expected `()`, found integer
error[E0308]: mismatched types
--> $DIR/loop-break-value.rs:159:15
|
LL | fn main() {
| - expected `()` because of this return type
@ -240,7 +316,7 @@ LL | loop { // point at the return type
LL | break 2;
| ^ expected `()`, found integer
error: aborting due to 20 previous errors; 1 warning emitted
error: aborting due to 25 previous errors; 3 warnings emitted
Some errors have detailed explanations: E0308, E0425, E0571.
For more information about an error, try `rustc --explain E0308`.